The present invention relates to a formalin sterilization apparatus for sterilizing, using formalin, an entire room such as an operation room or a patient's room in a hospital, for example.
A formalin sterilization apparatus of the type mentioned above is disclosed, for example, in Japanese Utility Model Publication sho 64-928. As shown in FIG. 3, this apparatus has a formalin container(31) and an ammonia water cotainer(35) which are connected to a heating chamber(34) by respective lines(33,37) provided with respective solenoid valves(32,36). Said heating chamber(34) is provided with a heater(38) and a vaporizing heater(39) for generating formaldehyde or ammonia gas. The heating chamber(34) is connected to a room(43) to be sterilized by a line(41) having a fan(40) and a bellows(42), and connected to said room(43) by another line(46) having a valve(47) and another bellows(45). A line(48) is divided from said line(46) at an upstream point of said valve(47) and communicated with the atmosphere via a valve(49) and an activated carbon container(50); a line(51) is divided from the line(46) at a downstream point of the valve(47) and communicated with the atmosphere via a valve(52) and a filter(53).
To perform sterilization and neutralization with formalin by this apparatus, first, the solenoid valve(36) and the valves(49,52) are closed and the solenoid valve(32) and the valve(47) are opened in order to feed formalin from the formalin cotainer(31) to the heating chamber(34). Formalin in the heating chamber(34) is then heated by the heaters(38,39) and vaporized into formaldehyde. This formaldehyde is fed by the fan(40) into the room(43) to be sterilized through the line(41) and the bellows(42) and is circulated to the heating chamber(34) through the bellows(45) and the line(46), thereby sterilizing the room(43) (sterilizing process).
The solenoid valve(32) and the valve(47) are then closed and the valves(49,52) are opened to feed clean air through the filter(53) into the the room(43), so that the formaldehyde in the room(43) is replaced by clean air. The exiting formaldehyde is passed through the activated carbon container(50) to be made harmless, and to be exhausted into the atmosphere (exhausting process).
The valves(49,52) are then closed and the solenoid valve(32) and the valve(47) are opened to feed ammonia water from the ammonia water cotainer(35) into the heating chamber(34), where the ammonia water is vaporized into ammonia gas by the heaters(38,39). Next, this ammonia gas is fed, by the fan (40), into the room(34), through the line(41) and the bellows(42), and then circulated to the heating chamber(34) through the bellows(45) and the line(46), thereby neutralizing formaldehyde remaining in the room(34) and in objects therein (neutralizing process). The ammonia gas is then exhausted into the atmosphere in the same way as in the previously mentioned exhausting process.
The apparatus as described above is, however, adapted to replace, in the exhausting process (after the formaldehyde sterilization process), formaldehyde in the room to be sterilized by clean air containing no bacterium or the like. For this reason the apparatus must have, in addition to a system for generating and circulating formaldehyde, a separate system including a filter and a line for intrducing clean air, and valves for switching these systems; it is therefore complicated in structure.
Also, because the prior apparatus is not adapted to precisely control the amount of formalin and ammonia water in the heating chamber, and the vaporizing temperature thereof, the formalin and ammonia water can overflow the heating chamber, or the amounts and temperatures of the generated formaldehyde and ammonia gas, for example, are not uniform and this has an adverse effect on the sterilizing and neutralizing actions.